Some Useful Technicalities
One simple example of illustrating a model is to add the fitted regression line to the data. We have already done this on several occasions, and Figure 12.1 repeats two of our examples. In both cases, the lines are just the predictions according to the fitted model in dependence on the covariate values. In the case of the logistic model on the right side of the figure, the predictions are shown on the probability scale.